In recent years, environmental pollution has become a social issue. With regulation of the use of phosphate as an ingredient in detergents, an enzyme has been mixed with a detergent to improve detergency. Detergents with an enzyme such as protease, amylase, cellulase and lipase are currently marketed. Particularly, protease can degrade organic stains of clothes, 10 to 40% of which are caused by proteins and which cannot be cleaned with conventional detergents. Protease has become an essential ingredient improving detergency.
As protease for detergents, there are many enzymes originated from microorganisms which are active in the alkaline pH range, and proteases such as Kazusase (Showa Denko K. K.), Savinase (Novo), Maxacal (Gist), Alcalase (Novo) and Biosam (Showa Denko K. K.) have been used. With spreading of automatic dish washers, an enzyme usable for automatic dish washers is being required. Protease is effective on protein stains on dishes from egg yolk, dairy products, etc. However, generally inactivation of enzymes is accelerated in an aqueous solution at high temperature. Thus, an enzyme having an advantage in stability is required. Although Esperase (Novo), etc. have been currently used for this purpose, these enzymes do not have entirely satisfactory activity and stability. The protease which is known to be the most stable in surfactants at present is a protease produced by Bacillus strain SD 521 (patent application number 191781 of 1991). However, an even more stable protease is desired.
Therefore, the object of the present invention is to provide an alkaline protease more stable in the presence of a surfactant, manufacturing method of the alkaline protease, use of the protease for detergent, etc., and a microorganism producing the protease.